Psoriasis is an inflammatory condition of the skin that

Mayo Clin Proc, September 2001, Vol 76 Topical Therapies for Localized Psoriasis 943 Concise Review for Clinicians Concise Review for Clinicians Topical Therapies for Localized Psoriasis PATRICIA M. WITMAN, MD Psoriasis is a chronic inflammatory condition of the skin with pronounced physical and psychosocial implications. This common condition affects 1% to 2% of the US population and is encountered frequently by nondermatologists and dermatologists. Fortunately, most patients have limited psoriasis, involving less than 5% of their body surface area. Although no cure is available, several topical therapies can minimize the disease in such patients. This article reviews the topical medications currently available for the treatment of psoriasis and provides an approach to patients with localized disease. Mayo Clin Proc. 2001;76:943-949 Psoriasis is an inflammatory condition of the skin that affects 1% to 2% of the US population. 1 Although seldom life-threatening, psoriasis can be a debilitating chronic illness with pronounced physical, psychological, and social implications. Patients with psoriasis experience itching, scaly, painful, and disfiguring skin lesions. Approximately 5% to 8% of patients with psoriasis also have psoriatic arthritis, which can be painful and compromise mobility. 2 Patients with psoriasis describe feelings of selfconsciousness, helplessness, embarrassment, anger, and frustration. Those with severe psoriasis report missing work frequently and increased unemployment because of psoriasis. 1 Multiple studies show an association between high alcohol consumption and severe psoriasis. 3 Available data suggest that increased problems with alcohol reflect the psychosocial burden of psoriasis, rather than the alcohol acting as a triggering factor. 3 Although there is no cure for psoriasis, several available treatments can minimize the skin lesions and associated symptoms. Some treatments can also induce remissions of months to years. The type of treatment indicated primarily depends on the severity of disease or extent of involvement, but other factors including expense, adverse-effect profile, patient preference, and availability (in the case of phototherapy) are also considerations. Most patients with psoriasis have limited disease, involving less than 5% of their body surface area. 4 For such patients, topical therapy is usually sufficient. For patients with more than 20% body surface involvement or those in whom topical treatments are ineffective, phototherapy and systemic therapies, including acitretin, methotrexate, and cyclosporine, are From the Department of Dermatology, Mayo Clinic, Rochester, Minn. A question-and-answer section appears at the end of this article. Address reprint requests and correspondence to Patricia M. Witman, MD, Department of Dermatology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (e-mail: witman.patricia@mayo.edu). available. Phototherapy and systemic medications have increased risks and optimally should be administered by experienced dermatologists. The National Center for Health Statistics reported that 2.25 million patients visited ambulatory care centers requesting treatment of psoriasis in 1996. 1 Although a large proportion of these patient visits were likely to dermatologists, primary care clinicians are often the first to confront management of psoriasis. This article aims to provide an overview of the available topical medications for psoriasis and an approach to patients with localized disease. CLINICAL FEATURES AND PATHOPHYSIOLOGY The cutaneous lesions of psoriasis are typically so distinctive that a diagnosis can be made based on clinical features alone. Well-demarcated, erythematous plaques with silvery scales that arise most commonly on the extensor surfaces of the elbows and knees, lumbosacral region, and scalp characterize the most common variety termed psoriasis vulgaris or the chronic plaque type. This form accounts for 90% of cases of psoriasis. Changes in the nails including pits, areas of yellow or brown discoloration known as oil spots, and a yellowed, thickened nail plate (often mistaken for onychomycosis) can occur in 50% of patients with psoriasis and can be helpful clues toward making the diagnosis. 2 Other clinical varieties of psoriasis exist including the guttate form, which often presents abruptly with multiple droplike small lesions scattered diffusely on the trunk and proximal extremities. This type is seen frequently in children and young adults, often preceded by a streptococcal throat infection. Inverse psoriasis presents as moist erythematous plaques in the axillae, inframammary regions, and groin. Generalized erythema and exfoliation characterize erythrodermic psoriasis. Other forms include generalized pustular psoriasis and palmar-plantar pustular psoriasis. 2 All these subtypes of psoriasis can be difficult to recognize, and in light of their more generalized and some- Mayo Clin Proc. 2001;76:943-949 943 2001 Mayo Foundation for Medical Education and Research

944 Topical Therapies for Localized Psoriasis Mayo Clin Proc, September 2001, Vol 76 times resistant nature, they are often best managed by a dermatologist. Despite continued active research in psoriasis, the exact etiology remains unknown. A genetic predisposition is suspected based on increased prevalence among family members and association with certain HLA subtypes. Psoriasis is known to be a disorder of hyperproliferation of epidermal keratinocytes, with both an increase in the number of cells actively dividing and an 8-fold decrease in the time required for the epidermal cells in psoriatic plaques to divide. Numerous activated T cells, alterations in Langerhans cells and phagocytic macrophages, and up-regulation of immune-mediated adhesion molecules on keratinocytes have also been noted within psoriatic lesions, supporting an immune system etiology. Moreover, involvement of the immune system is suggested by the improvement of psoriasis with treatment modalities, such as cyclosporine, that reduce cutaneous T-cell infiltration. 2 TRIGGERING FACTORS Of importance, the clinician should be familiar with factors that can trigger or flare psoriasis because awareness of these can affect management of psoriasis. The Koebner phenomenon describes the development of a skin condition or its worsening in an area of epidermal injury. Psoriasis is one of several conditions characterized by this phenomenon, and, as a result, will flare in areas of sunburn, surgical incisions, and traumatized skin. Thus, picking or manipulating psoriatic skin lesions should be discouraged. Several medications have been implicated to trigger psoriasis, including antimalarials, lithium, β-blockers, angiotensin-converting enzyme inhibitors, quinidine, and nonsteroidals. 2,5 When an acceptable alternative exists, avoidance or discontinuation of an aggravating medication can be helpful. Withdrawal of systemic corticosteroids can result in a dramatic flare of psoriasis, often leading to a serious generalized form of pustular psoriasis, the von Zumbusch variety. In addition to skin findings of generalized erythema, desquamation, and pustule formation, the affected patient can become systemically ill with high fever, hypotension, weight loss, and hypocalcemia. This subtype can occasionally be fatal. 2 As a rule, systemic corticosteroids should never be used to treat chronic plaque psoriasis, and systemic corticosteroids must be used with extreme caution in patients with psoriasis in whom corticosteroids are being used for other indications. 6 Infections can also flare psoriasis. Streptococcal pharyngitis and other streptococcal infections are well-known triggers of psoriasis, and appropriate antimicrobial therapy often hastens resolution of the psoriatic lesions. Viral infections can also trigger psoriasis. In particular, patients infected with the human immunodeficiency virus have been reported to have a higher incidence of psoriasis than the general population. 3 Other aggravating factors of psoriasis include stress and climate. 3 Cold winter months are associated with increased flares of psoriasis, whereas warm sunny weather has an opposite effect. During the summer months, patients with psoriasis will improve with judicious exposure to natural ultraviolet light; however, patients must be careful not to sunburn as this may result in a flare due to the Koebner phenomenon. Use of tanning beds by patients should be discouraged because they are often ineffective for psoriasis and are not monitored carefully. Thus, several factors can lead to a flare of psoriasis. The clinician s awareness of these factors and education of patients regarding them can be as essential as the medications used to treat psoriasis. TOPICAL THERAPY Several topical therapies are available for the treatment of psoriasis (Table 1). These therapies are a reasonable choice in the patient with limited plaque psoriasis or less than 20% involvement of body surface area. When one estimates percentage of body surface involvement, the size of the palm of a hand approximates 1% of body surface area. 7 The best agent to use depends on several factors, including anatomical site being treated, patient preference, cost of medication, likelihood of remission, and patient willingness to comply. Occasionally, combination therapy with more than 1 medication may be helpful. Emollients Regular use of an emollient or moisturizer is important. These products produce an occlusive film that limits evaporation of water from the skin and allows the stratum corneum to rehydrate itself. Patients with psoriasis should be encouraged to take a daily bath in warm water followed by generalized application of a cream or ointment moisturizer. A second or third application of a moisturizer during the day is also beneficial. These measures alone can lead to improvement of psoriasis in many patients. Hydration of the stratum corneum can also lead to enhanced delivery of other medications, such as corticosteroids. 8 Several products are available, including bath oils, moisturizing creams, and ointments. Creams or ointments are preferable to lotions because they tend to be thicker, more occlusive, and therefore more effective. Putting oils in the bath water can also be helpful but should be avoided in elderly patients at high risk of falling in their bathtub. Keratolytics Keratolytic agents are helpful in reducing scale and hyperkeratosis by causing softening and desquamation of

Mayo Clin Proc, September 2001, Vol 76 Topical Therapies for Localized Psoriasis 945 Table 1. Topical Therapies for Psoriasis Patient Duration of Therapy Formulation acceptance Cost Efficacy remission Adverse effects Emollients Multiple OTC lotions, Excellent Inexpensive Typically does not result in Not applicable None reported creams, ointments, clearance as a monobath oils therapy; used in combination with other therapies Salicylic acid Compounded by Excellent Can be more Typically does not result in Not applicable Risk of salicylate pharmacist in expensive if clearance as a mono- toxicity with concentrations of compounded therapy; used in combina- application to 2% to 10% in white tion with corticosteroids >20% body petrolatum or other to decrease amount of surface area base; OTC scalp scale solutions, shampoos Corticosteroids Multiple gels, lotions, Excellent Varies; generic Thinning of plaques, Mean duration of Local: striae, creams, ointments, formulations decreased symptoms in 2 mo with atrophy, hyposolutions, scalp available first 2 wk of treatment, betamethasone pigmentation, foams grouped by with improvement in dipropionate telangiectasias, relative strength subsequent weeks ointment; rebound folliculitis, (classes 1-7) phenomenon may hirsutism occur, making Systemic: risk of abrupt cessation suppression of of medication HPA axis with undesirable excessive and prolonged use Tar Crude coal tar, liquor Poor* Inexpensive; Thinning of plaques, Prolonged, Irritation, carbonis detergens, can be more decreased symptoms in particularly when folliculitis, tar shampoos expensive if 2-4 wk combined with photosensitivity compounded ultraviolet B light Anthralin Commercial Poor Inexpensive; Thinning of plaques, Prolonged Extremely formulations, can be more decreased symptoms in (3.9-6 mo) irritating; must compounded expensive if 2-4 wk avoid contact to formulations compounded surrounding skin Vitamin D Calcipotriene Good Expensive As effective as class 2 Mean of 43.3 d; Irritation; risk of analogues ointment, cream, corticosteroids but often long-term therapy hypercalciuria scalp solution takes 6-8 wk for full necessary and hypereffect calcemia with >100 g in a week Retinoids Tazarotene 0.05%, Good Expensive As effective as class 2 Prolonged Irritation; must be 0.1% gel or cream corticosteriods; improve- compared to used with ment noted in first 2 wk fluocinonide extreme caution of therapy (class 2 cortico- in women of steroid) childbearing age (category X) *Stains clothing and skin, has unpleasant odor, and causes irritation. Stains clothing, skin, and other objects a purple color and causes irritation. Irritation occurs in 15% to 20% of patients especially in groin and on face. Irritation occurs in 30% of patients. HPA = hypothalamic-pituitary-adrenal; OTC = over-the-counter. the stratum corneum. They are most beneficial in extremely thick or scaly psoriatic plaques. The keratolytics include urea, lactic acid, and salicylic acid. Urea and lactic acid are available in several commercial moisturizing creams and lotions. Salicylic acid is the most effective of the keratolytics and is found in several over-thecounter medicated shampoos and scalp solutions aimed at treatment of the scalp as well as in compounded ointments helpful for localized psoriasis elsewhere on the body. 9 Although salicylic acid can be helpful as a monotherapy, it is most commonly used in combination with a corticosteroid, which allows enhanced corticosteroid penetration. Concentrations of salicylic acid used for this means are 2% to 10%. Unfortunately, at present, no premixed combination compounds (salicylic acid in combina-

946 Topical Therapies for Localized Psoriasis Mayo Clin Proc, September 2001, Vol 76 tion with a corticosteroid) are commercially available in the United States. All such combinations require compounding by a pharmacist and carry the risk of imprecise formulations that are potentially unstable, unsafe, or ineffective. Requesting a compound of salicylic acid in pure white petrolatum and asking the patient to use it concurrently with a corticosteroid is the most likely approach to guarantee that the products remain stable. Compounding by a pharmacist increases cost and is associated with the risk of pharmaceutical error. Anecdotal reports have described pharmacists compounding aspirin when salicylic acid was requested. Salicylate toxicity is also a possibility with widespread application of salicylic acid; therefore, such compounds should never be applied to more than 20% of the body surface area and should be applied only to the thickest, scaliest plaques. 9 Corticosteroids Topical corticosteroids are the most commonly prescribed medication for the treatment of psoriasis in North America. 8 Topical corticosteroids have anti-inflammatory, antiproliferative, and immunosuppressive effects, and direct application to psoriatic lesions can result in rapid improvement in both the appearance and the symptoms associated with such plaques. Several topical corticosteroids are available in various strengths and different vehicles. Thus, the clinician can tailor the prescribed treatment dependent on the anatomical sites and patient preferences. In general, ointments are the most effective because their occlusiveness leads to increased corticosteroid penetration. They are also most helpful for extremely dry skin lesions. Creams are not as effective as ointments, but they are less greasy and therefore better tolerated by patients. Lotions and solutions tend to be fluid compounds that work best in hair-bearing areas such as the scalp. Gels are often alcohol- or acetone-based compounds that have good penetration but can be drying to the skin; they also work well in hair-bearing areas. Finally, the new corticosteroid mousses are particularly efficacious and well tolerated on the scalp. 10 Topical corticosteroids are categorized based on their relative strengths with class 1 being the strongest, also termed super potent corticosteroids, and classes 6 and 7 being the weakest. Close attention must be given to the vehicle in which a corticosteroid is prescribed because the vehicle can alter the strength substantially. In general, ointments are most potent, followed by creams and then lotions. Occlusion by applying saran wrap over a medication can also increase penetration and efficacy. In general, class 1 corticosteroids should be reserved for treatment of inflammatory skin conditions on thicker-skinned areas, such as palms, soles, elbows, and knees, and should not be used continuously for more than 2 weeks to minimize risk of corticosteroid adverse effects. The class 6 and 7 corticosteroids are ideal for use in thin-skinned areas, such as the face and the intertriginous folds of the groin and axilla. Although corticosteroids can be effective, they have several potential adverse effects, and therefore close surveillance by the prescribing physician is necessary. Skin atrophy, telangiectasias, hypertrichosis, hypopigmentation, stretch marks, and systemic absorption with associated adrenal suppression are all potential complications of topical corticosteroid use. 6 The risk of adverse effects increases with increased potency of the corticosteroid and with duration of use. As a general rule, the weakest corticosteroid that is efficacious should be used for any inflammatory skin condition. Compared with other inflammatory conditions of the skin, chronic plaque psoriasis often requires treatment with a class 1 or 2 corticosteroid to achieve clearance. To avoid systemic corticosteroid absorption, less than 50 g per week of a class 1 corticosteroid should be used. 1 As a reference, approximately 400 g of a topical agent is needed to cover an entire body surface area twice daily for a week. 1 Therefore, topical corticosteroids used as monotherapy are most appropriate for psoriasis involving less than 10% of total body surface area. In this instance, a class 1 or 2 corticosteroid can be applied twice daily to involved areas until improvement is noted (usually 2-4 weeks), at which time the corticosteroid strength can be tapered to a class 3 or 4 corticosteroid for twice daily or less frequent use. Another tapering strategy involves continuing the class 1 or 2 corticosteroid but decreasing the frequency of application to 3 times in a 36-hour period each weekend, an approach termed pulse dosing or weekend therapy. 8 Of importance, class 1 or 2 corticosteroids should never be used on a patient s face or in intertriginous folds even for short-term application. In these areas, a class 6 or 7 corticosteroid should be used. The clinician should be aware that psoriasis often recurs promptly after discontinuation of topical corticosteroid treatment. The mean duration of remission is approximately 2 months in studies in which betamethasone dipropionate ointment (class 2 corticosteroid) was discontinued abruptly. 11 In addition, withdrawal of topical corticosteroids can lead to a rebound phenomenon with acute worsening of the inflammation in the plaques in which corticosteroid use was discontinued. Moreover, tachyphylaxis, a loss of efficacy of a topical medication after longterm use, can occur with corticosteroids. Therefore, although corticosteroids can be useful for limited psoriasis, they have several disadvantages. Corticosteroids can sometimes be used more effectively in combination with other topical agents, as described subsequently.

Mayo Clin Proc, September 2001, Vol 76 Topical Therapies for Localized Psoriasis 947 Tar and Anthralin Tar and anthralin are some of the oldest and safest topical therapies available for the treatment of psoriasis. Although the exact mechanism of action of both of these medications remains unknown, they are highly effective in clearing psoriasis and tend to result in a prolonged remission time. They are particularly helpful in patients in whom corticosteroids or other topical medications are ineffective or when topical corticosteroids are not safe or practical because of involvement of large body surface area. 12 Tar is used most routinely in the Goeckerman treatment in which crude coal tar is applied in a generalized manner to the skin and combined with daily ultraviolet B treatments in either a hospital or day treatment program. The Ingram therapy, more popular in Europe, involves topical anthralin used in combination with ultraviolet B treatments. 12 Both are extremely effective and safe treatments with prolonged remission times. Studies evaluating the Goeckerman treatment report remission in 90% of patients after 8 months, with 75% remaining clear for a year or more. 11 The inconvenience and cost of the Goeckerman treatment along with the advent of managed care have made it less popular in recent years; however, it remains an ideal choice in patients with severe psoriasis because of its efficacy, prolonged remission, and high safety profile. Tar can also be used to treat psoriasis in outpatients. Crude coal tar is available in several commercial products or can be compounded in a petrolatum base by a pharmacist. Although it is efficacious and lacks the potential adverse effects of topical corticosteroids, its unpleasant odor and staining of skin, fabrics, and other objects make it difficult to use for most outpatients. Liquor carbonis detergens solution is a less potent tar mixed in white petrolatum (for the body) or in oil (Nivea) (for the scalp) with a concentration of 5% to 20%. Liquor carbonis detergens is more tolerable with less staining. All tar products can cause irritation, folliculitis, and phototoxicity. The most commonly used tar products are the tar shampoos, which can be helpful for scalp involvement. 12 Anthralin (also known as dithranol) is available in commercial concentrations of 0.1% to 1% in a cream or ointment base, but higher concentrations can be compounded by a pharmacist. It is most commonly used as the active agent in short-contact anthralin therapy in which escalating concentrations of the medication are directly applied to psoriatic plaques and left on for gradually increasing increments before being washed off (usually 5-30 minutes). Anthralin stains skin, clothing, bathtubs, and other objects a purple color, limiting its acceptance by many patients. It can also irritate the skin substantially. 12 Despite these negative features, anthralin works well to clear psoriasis and is associated with prolonged remission after discontinuation of the medication, ranging from 3.9 to 6 months. 11 An anthralin preparation was released recently that reportedly minimizes staining of household items. The anthralin in this compound (Micanol) has been placed in a vehicle that only releases the drug at the temperature of the body s skin. 10 Vitamin D Analogues Vitamin D 3 is known to inhibit keratinocyte proliferation, enhance cellular differentiation, and possess immunomodulating activities. When given orally, it can improve psoriasis but can also lead to hypercalcemia and hypercalciuria. 5 Calcipotriene is a topical vitamin D 3 analogue that became available in 1993 for the treatment of plaque psoriasis. 8 It has activity similar to vitamin D 3 in regard to cellular proliferation and differentiation but is much less potent in affecting calcium homeostasis. 5 Calcipotriene is available in an ointment base, the most occlusive and effective form, and as a cream formulation that is less greasy and may have improved patient acceptance. A calcipotriene solution is also available for scalp psoriasis. All therapeutic forms work best if applied twice daily to the areas of psoriasis. The recommended maximal weekly dose of calcipotriene is 100 g to prevent potential systemic effects on calcium metabolism. Although a therapeutic response may be noted within 2 weeks, 6 to 8 weeks of therapy are required to see the maximal effect. Improvement is not as rapid as with corticosteroids, but calcipotriene is as efficacious as fluocinonide ointment (class 2 corticosteroid) in clearance of psoriasis without the associated corticosteroid adverse effects. Tachyphylaxis is not a problem. 13 Relapse will occur in a mean of 43.3 days after discontinuation of therapy; therefore, long-term use of the medication is often necessary for maintenance. 11 The most common adverse effect of calcipotriene is irritation. It occurs in 15% to 20% of patients, and although many patients become accustomed to this, 2% to 3% of patients in clinical studies had to discontinue the medication because of persistent irritation. Skin irritation may also limit use of this medication in thin-skinned areas such as the face and groin. Although it is being used in children, calcipotriene has not been thoroughly studied in the pediatric age group, and the maximal amount that can be used safely to avoid systemic effects in children is unknown. 13 Calcipotriene tends to be more expensive than corticosteroids because no generic forms are available. Retinoids Retinoids are biologic derivatives of vitamin A that affect keratinocyte proliferation and differentiation. 5

948 Topical Therapies for Localized Psoriasis Mayo Clin Proc, September 2001, Vol 76 Tazarotene was the first topical retinoid approved by the Food and Drug Administration for use in plaque psoriasis in 1997. 1 It is available in a 0.1% and 0.05% gel formulation, as well as a recently released 0.1% and 0.05% cream formulation. A pea-sized amount is sufficient for a palmsized area and should be rubbed into psoriatic plaques once to twice daily; surrounding areas should be avoided. 5 In studies examining the clearance of psoriasis, tazarotene gel was as effective as class 2 corticosteroids with the advantage of a substantially prolonged remission over that of corticosteroids. Only 18% of patients treated with tazarotene had a relapse 12 weeks after therapy was discontinued compared with 55% of patients treated with topical fluocinonide. 11 Local skin irritation is the most frequent adverse event associated with tazarotene use. It occurs in 30% of patients, with the highest incidence being noted with the 0.1% gel. 1 The new cream formulations are being marketed as less irritating. Like calcipotriene, tazarotene is typically more expensive than some of the other topical medications because generic forms are not available. Tazarotene is category X and therefore should never be used in pregnant or lactating female patients. This fact must be considered before the medication is prescribed to women of childbearing age. Some experts advocate the use of a baseline pregnancy test before prescribing the medicine. 4 COMBINATION REGIMENS No single antipsoriasis topical medication is perfect by itself in the management of topical psoriasis; therefore, combination regimens, using medications from different categories, can often be beneficial. As mentioned previously, generalized use of an emollient will be a helpful addition to any topical therapy for psoriasis. Salicylic acid, by reducing excess scale, can be used concurrently with corticosteroids to increase their penetration and efficacy in the treatment of thick or scaly plaques. However, salicylic acid should not be used concurrently with calcipotriene because calcipotriene is inactivated by the acidic nature of salicylic acid. 10 Alternating topical corticosteroids with another topical medication decreases corticosteroid use and potential corticosteroid adverse effects; any of the topical medications can be used. One of the more frequently used combination regimens is calcipotriene with a class 1 corticosteroid. This approach involves application of calcipotriene once daily and a class 1 corticosteroid at an alternative time each day. The corticosteroid has a more rapid effect on the psoriatic plaque and allows the patient to see improvement in the first few weeks of therapy. It also counteracts some of the irritation induced by calcipotriene, making the therapy more tolerable and the psoriatic plaques less erythematous. After 2 to 3 weeks, the corticosteroid should be tapered in frequency to avoid skin thinning and other adverse effects. Abrupt discontinuation of the corticosteroid results in a flare of psoriasis; therefore, the patient should be instructed to taper the medication by applying calcipotriene twice daily on weekdays with the class 1 corticosteroid being used twice daily on weekends. This strategy can be continued until clearance is achieved, at which time the corticosteroid is discontinued, and the patient is maintained on calcipotriene once to twice daily. 13 Tazarotene can be effective in a combination regimen with corticosteroids. When tazarotene is applied once daily with a corticosteroid being used once daily at an alternative time, the rate of clearance of psoriasis is more rapid compared with tazarotene alone. 14 The corticosteroid also helps to counteract the pronounced irritation that otherwise can limit tazarotene s use. The use of tazarotene helps potentiate a longer remission time and avoids the potential adverse effects of twice-daily corticosteroid use. In summary, effectively combining topical therapies from different categories allows the clinician to optimize the positive characteristics of a medication while avoiding or counteracting the adverse effects associated with that medication. CONCLUSION Major strides have been made in the past decade in the development and improvement of medications useful in the topical treatment of psoriasis. New formulations of corticosteroids with increased efficacy and new vehicles with improved patient acceptability continue to be developed. The first topical vitamin D 3 analogue, calcipotriene, and the first topical retinoid, tazarotene, are prime examples of the advances being made. Other topical treatments are on the horizon. New vitamin D analogues are currently being developed and tested. 10 Further advances in topical retinoids can be expected. Although more studies are needed, a topical methotrexate formulation has been reported as being helpful in treating mild to moderate psoriasis. 10 Psoriasis is a chronic skin disease that causes pronounced morbidity in a large number of patients. Although no cure is available, several therapies are effective in clearing psoriasis. The clinician who is familiar with these topical medications will be better equipped to assist in the care of patients with limited psoriasis. For patients who have more extensive involvement or in those in whom topical therapies are ineffective, referral to a dermatologist experienced in other treatments, such as phototherapy, acitretin, methotrexate, cyclosporine, and the Goeckerman treatment, is recommended.

Mayo Clin Proc, September 2001, Vol 76 Topical Therapies for Localized Psoriasis 949 REFERENCES 1. Linden KG, Weinstein GD. Psoriasis: current perspectives with an emphasis on treatment. Am J Med. 1999;107:595-605. 2. Christophers E, Mrowietz U. Psoriasis. In: Freedberg IM, Eisen AZ, Wolff K, et al, eds. Fitzpatrick s Dermatology in General Medicine. Vol 1. 5th ed. New York, NY: McGraw-Hill; 1999:495-521. 3. Stern RS. Epidemiology of psoriasis. Dermatol Clin. 1995;13:717-722. 4. Tristani-Firouzi P, Krueger GG. Efficacy and safety of treatment modalities for psoriasis. Cutis. 1998;61(2, suppl):11-21. 5. Peters BP, Weissman FG, Gill MA. Pathophysiology and treatment of psoriasis. Am J Health Syst Pharm. 2000;57:645-659. 6. Hughes J, Rustin M. Corticosteroids. Clin Dermatol. 1997;15:715-721. 7. Koo JY. Current consensus and update on psoriasis therapy: a perspective from the U.S. J Dermatol. 1999;26:723-733. 8. Lebwohl M, Abel E, Zanolli M, Koo J, Drake L. Topical therapy for psoriasis. Int J Dermatol. 1995;34:673-684. 9. Lebwohl M. The role of salicylic acid in the treatment of psoriasis. Int J Dermatol. 1999;38:16-24. 10. Lebwohl M. Advances in psoriasis therapy. Dermatol Clin. 2000; 18:13-19. 11. Koo J, Lebwohl M. Duration of remission of psoriasis therapies. J Am Acad Dermatol. 1999;41:51-59. 12. Silverman A, Menter A, Hairston JL. Tars and anthralins. Dermatol Clin. 1995;13:817-833. 13. Koo J, Nguyen Q, Gambla C. Advances in psoriasis therapy. Adv Dermatol. 1997;12:47-72. 14. Lebwohl M, Poulin Y. Tazarotene in combination with topical corticosteroids. J Am Acad Dermatol. 1998;39(4, pt 2):S139-S143. Questions About Topical Therapies for Localized Psoriasis 1. Which one of the following is not a triggering factor for the development of psoriasis? a. Human immunodeficiency virus infection b. Streptococcal pharyngitis c. Alcohol abuse d. Cold weather e. Sunburn 2. Which one of the following is not a safe and effective treatment of chronic plaque psoriasis? a. Tar b. Anthralin c. Calcipotriene d. Systemic corticosteroids e. Topical corticosteroids 3. Which one of the following adverse events may occur if a patient exceeds 100 g of calcipotriene ointment in 1 week? a. Irritation b. Hypocalcemia c. Adrenal suppression d. Hypercalciuria e. Tachyphylaxis 4. Which one of the following must be used with extreme caution in women of childbearing age? a. Calcipotriene b. Tazarotene c. Corticosteroids d. Tar e. Urea 5. Which one of the following is not an effective combination regimen in the treatment of chronic plaque psoriasis? a. Calcipotriene and corticosteroids b. Tar and ultraviolet light c. Calcipotriene and salicylic acid d. Corticosteroids and salicylic acid e. Tazarotene and corticosteroids Correct answers: 1. c, 2. d, 3. d, 4. b, 5. c